Chronic Spontaneous Nephrocutaneous Fistula Associated With Renal Replacement Lipomatosis

RIU0458_12-07.qxd 12/21/10 7:39 PM Page e190 CASE REVIEW Chronic Spontaneous Nephrocutaneous Fistula Associated With Renal Replacement Lipomatosis A. Khallouk, MD, M. F. Tazi, MD, M. J. Elfassi, MD, M. H. Farih, MD Department of Urology, Hassan II Hospital University Center, Fez, Morocco Chronic spontaneous nephrocutaneous fistula is a rare renal disease. Renal replacement lipomatosis (RRL) is the result of the atrophy and destruction of renal parenchyma with massive increases in the amount of fat in the sinus and perirenal space. The 2 conditions can be associated because they may have the same etiology. Indeed, urolithiasis is the most common cause of these diseases. We report a case of chronic nephrocutaneous fistula associated with RRL due to both urolithiasis and renal tuberculosis. [Rev Urol. 2010;12(4):e190-e192 doi: 10.3909/riu0458] © 2010 MedReviews®, LLC Key words: Nephrocutaneous fistula • Renal replacement lipomatosis • Renal tuberculosis enal replacement lipomatosis (RRL) is a condition that associates parenchymal renal loss and massive proliferation of renal sinus, perinephric fat, and fibrous tissue. RRL is related to chronic inflammatory disease and is linked to renal calculus disease in 76% to 79% of reported cases.1 Chronic nephrocutaneous fistula is linked to various etiologies. Indeed, renal calculus is the most common cause,2,3 followed by chronic renal tuberculosis.4,5 We report a case of RRL and chronic nephrocutaneous fistula due to renal calculus and tuberculosis. R e190 VOL. 12 NO. 4 2010 REVIEWS IN UROLOGY RIU0458_12-22.qxd 12/22/10 4:06 PM Page e191 Chronic Spontaneous Nephrocutaneous Fistula Figure 1. Right loin of the patient with multiple discharging sinuses. with epithelioid cells and multinucleated cells were observed. Discussion Case Report A 45-year-old woman was admitted with complaints of chronic lumbar pain and recurrent fever. She had a 4-year history of lumbar discharge with multiple sinuses in her right loin (Figure 1). The physical examination revealed a tender mass in the right flank. Unenhanced computed tomography (CT) scan of the abdomen showed severe atrophy of the right renal parenchyma and multiple renal calculi (staghorn calculus; Figure 2). Additionally, there was a massive fatty proliferation within the renal sinus, hilus, and perinephric space (Figure 3). CT scan with contrast injection was not performed because the renal function was slightly impaired (serum creatinine, 24 mg/L). A preoperative Lowenstein culture was negative for Mycobacterium tuberculosis. A right nephrectomy was performed. Almost the total parenchyma of the kidney was replaced by adipose tissue. On microscopic study, tuberculous granulomas Figure 2. Computed tomography scan image showing renal replacement by adipose tissue and multiple calculi. Spontaneous chronic nephrocutaneous fistula is a rare manifestation of renal disease.4,6 The majority of such fistulas present as spontaneous drainage through lumbar region. The etiologies of nephrocutaneous fistula include chronic calculous disease, which is probably the most common cause,2,3,6-8 followed by chronic renal tuberculosis.4,5 Renal replacement lipomatosis is a severe loss of renal parenchyma with massive deposition of fat and fibrous tissue in the sinus and the perirenal space. This condition is usually associated with a state of long-standing inflammation. RRL and nephrocutaneous fistula may have the same etiology. Indeed, renal calculus is reported to be the cause of 76% to 79% of cases of RRL.1 Tuberculosis is also reported to cause replacement lipomatosis of the kidney.9 Clinical presentation is nonspecific in both diseases. The symptoms may include a tender mass in the flank, fever, hematuria, urinary tract infection, and weight loss. Rarely, the Figure 3. Computed tomography scan image showing massive proliferation of fat and severe atrophy of renal parenchyma. VOL. 12 NO. 4 2010 REVIEWS IN UROLOGY e191 RIU0458_12-07.qxd 12/21/10 7:39 PM Page e192 Chronic Spontaneous Nephrocutaneous Fistula continued patients are asymptomatic. Some patients often overlook minor and neglected complaints of flank pain and imaging (MRI), and dimercaptosuccinic acid renal scintigraphy—may be necessary to establish if the kidney is Some patients often overlook minor and neglected complaints of flank pain and backache due to an underlying perinephric abscess that may lead to spontaneous nephrocutaneous fistula. backache due to an underlying perinephric abscess that may lead to spontaneous nephrocutaneous fistula. The clinical features related to renal tuberculosis are variable and range from simple fatigue, anorexia, and weight loss associated with urinary symptoms, hematuria, and loin pain. Renal tuberculosis may be diagnosed by the identification in urine of M tuberculosis by acid-fast bacilli stain. The culture remains the gold standard for detection of M tuberculosis and demonstrates the sensitivity of various antituberculosis drugs. Recently, the nucleic acid amplification test has demonstrated an effective and important role in the diagnosis.10 One or more investigations—plain radiography, abdominal sonography, fistulography, intravenous urography, CT scan, magnetic resonance functional and to diagnose the underlying etiology. However, CT remains the most accurate method of demonstrating renal changes and the underlying etiology. Indeed, CT scan enables an accurate diagnosis of RRL and aids in the differential diagnosis of fat-containing masses, such as retroperitoneal liposarcoma, renal lipoma, and angiomyolipoma.9 MRI provides further confirmation of RRL.9 We must keep in mind that the diagnosis of renal tuberculosis is sometimes made only on histopathological examination. Conclusions Nephrocutaneous fistula and renal replacement lipomatosis are rare, and few cases are reported in the literature. They are related to an underlying chronic inflammatory disease. In the case of chronic evolution of the fistula, even in the presence of urolithiasis, we must keep in mind the possibility of associated renal tuberculosis. References 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Honda H, MacGuire CW, Barloon TJ, Hashimoto K. Replacement lipomatosis of the kidney: CT features. J Comput Assist Tomogr. 1990;14:229231. Iseki T, Kawamura M. Spontaneous passage of renal calculi through nephrocutaneous fistula due to calculous pyelonephritis. Br J Urol. 1987;59:285-286. Lewi HJE, Scott R. Calculocutaneous sinus. Urology. 1986;28:232-234. Ansari MS, Singh I, Dogra PN. Spontaneous nephrocutaneous fistula—2 unusual case reports with review of literature. Int Urol Nephrol. 2004;36:239-243. Qureshi MA. Spontaneous nephrocutaneous fistula in tuberculous pyelonephritis. J Coll Physicians Surg Pak. 2007;17:367-368. Charles JC. Nephrocutaneous fistula. J Natl Med Assoc. 1990;82:589-590. Singer AJ. Spontaneous nephrocutaneous fistula. Urology. 2002;60:1109-1110. Kiris A, Kocakoc E, Poyraz AK, et al. Xantogranulomatous pyelonephritis with nephrocutaneous fistula and coexisting renal replacement lipomatosis: the report of a rare case. J Clin Imaging. 2005;29:356-358. Casas JD, Cuadras P, Mariscal A, Domenech S. Replacement lipomatosis related to renal tuberculosis: imaging finding in one case. Eur Radiol. 2002;12:810-813. Takahashi S, Hashimoto K, Miyamoto S, et al. Clinical relevance of nucleic acid amplification test for patients with urinary tuberculosis during antituberculosis treatment. J Infect Chemother. 2005;11:300-302. Main Points • The etiology of nephrocutaneous fistula includes chronic calculous disease, which is probably the most common cause, followed by chronic renal tuberculosis. • Renal replacement lipomatosis (RRL) is a severe loss of renal parenchyma with massive deposition of fat and fibrous tissue in the sinus and the perirenal space. This condition is usually associated with a state of long-standing inflammation. • RRL and nephrocutaneous fistula may have the same etiology. Indeed, renal calculus is reported to be the cause of 76% to 79% of cases of RRL. Tuberculosis is also reported to cause replacement lipomatosis of the kidney. The clinical features related to renal tuberculosis are variable and range from simple fatigue, anorexia, and weight loss associated with urinary symptoms, hematuria, and loin pain. e192 VOL. 12 NO. 4 2010 REVIEWS IN UROLOGY